1. Field of the Invention
This invention relates generally to manufacturing integrated circuit devices and, more particularly, to an automated integrated circuit device manufacturing facility employing a centralized control system.
2. Description of the Related Art
A semiconductor fabrication facility typically includes numerous processing tools used to fabricate semiconductor devices. The processing tools may include photolithography steppers, etch tools, deposition tools, polishing tools, rapid thermal processing tools, ion implantation tools, and the like. Wafers (or wafer lots) are processed in the tools in a predetermined order and each processing tool modifies the wafers according to a particular product design and/or operating recipe so that a desired product is formed in or on the wafer. For example, a photolithography stepper may be used to form a patterned layer of photoresist above the wafer. Features in the patterned layer of photoresist correspond to a plurality of features, e.g. gate electrode structures, which will ultimately be formed above the surface of the wafer.
Operation of the processing tools in the semiconductor fabrication facility is generally controlled by a variety of control units, each of which is responsible for a different aspect of the fabrication process. For example, the semiconductor fabrication facility may include one or more materials handling controllers that may be responsible for providing necessary materials to the processing tools. The materials controlled by the material handling controllers may include wafers, test wafers, chemicals and/or gases used in the processing, and the like. The semiconductor fabrication facility may also include one or more wafer control units, such as run-to-run (RtR) controllers, Fault Detection and Control (FDC) controllers, Contamination Free Manufacture (CFM) controllers, and the like that may be used to monitor the wafers and/or modify the operating recipes, e.g., if faults or defects are detected. One or more excursion/exception controllers may be included to detect tool failures, shortages of supplied chemicals and/or gases, and the like. A data systems network is typically included to control the exchange of data between the processing tools and the various controllers and a planning system and control unit may be used to determine priorities associated with different products formed on the wafers processed in the semiconductor fabrication facility. Controllers may also be associated with particular types of processing tools, such as photolithography tools, etching tools, chemical mechanical polishing tools, and the like.
The control units in the semiconductor fabrication facility operate largely independently of one another. For example, the materials handling controllers may make decisions regarding provision of wafers, chemicals, and/or gases to one or more processing tools based on information collected from the processing tools. However, the materials handling controllers may not account for data collected by, or actions taken by, other control units such as the wafer control units, the excursion control units, the data systems network, and/or the planning systems controller. For another example, a photolithography tool controller may take actions to control operation of one or more photolithography tools independently of the state of other tools (e.g., etching tools, diffusion tools, chemical mechanical polishing tools, metrology tools, wafer electrical test tools, and the like) that may be a part of the same process flow as the controlled photolithography tools.
The independent nature of the various control units may make it difficult to coordinate operations of the control units to achieve global goals of the semiconductor fabrication facility. For example, the number of each type of product formed by the semiconductor fabrication facility, as well as the deadlines for producing these products, may be determined by forces such as current market demand for each product, shipping commitments made to clients, lot requests by research and development teams, and the like. In a conventional semiconductor fabrication facility, engineers manually configure the various control units to attempt to meet the global goals. This process is time-consuming, may reduce the efficiency of the semiconductor fabrication facility, and is not always successful. Furthermore, if any of the forces that determine the global goals should change, the various control units must be manually reconfigured to attempt to meet the changing goals.